People have done many an irrational thing due their fear of spiders but setting a petrol station alight is probably one of the most extreme.

A man who apparently suffers from arachnophobia caused a fire at a Detroit petrol station when he set a lighter to what he says was a spider near his fuel door.

Station clerk Susan Adams told local media that he pulled up and "that's when he pulled the lighter out of his pocket and lit it and started the fire."

The man was uninjured and Adams shut off the fuel pump from inside the station before calling the fire brigade.

Surveillance video at the petrol station reportedly reveals the man said, "Is that a spider in there?" before flames erupted. However, he was later reticent about what had actually happened, according to Adams.

However, he later admitted to fire investigators that he has a fear of spiders.